Charles Bonnet syndrome in leprosy; prevalence and clinical characteristics.

Charles Bonnet syndrome (CBS) is diagnosed when a visually impaired patient without any mental disorder develops visual hallucinations. A survey of patients in a National Leprosarium revealed that the point prevalence of CBS in leprosy was 0.4%. This prevalence appears to be high, as few cases with CBS have been reported. The semeiology of visual hallucinations was typical of CBS. However, the clinical features were different from previous reported cases because of the history of leprosy and associated multi-sensory loss. Patients with leprosy appear to be at increased risk for CBS, due to frequent eye complications combined with sensory loss, ageing, and intact intellectual functions.